The present invention relates to an optical apparatus and relates to an optical apparatus mainly used for an optical disk apparatus of recording/reproducing type.
In recent years, optical disk apparatuses have been widely used as media for reproducing sounds and pictures. Further, optical disk recording/reproducing apparatuses for not only reproducing but also recording data on optical disks have been manufactured and used.
In an optical disk recording/reproducing apparatus of this type, a laser beam is used for both recording and reproduction in the optical system of the apparatus. Due to this, it is impossible to check whether recorded data of, for example, a picture is suited for reproduction while recording the picture on an optical disk. To check the recording state, it is required to record all or part of pictures on the optical disk and then reproducing the recorded pictures.
In other words, in a conventional optical disk recording/reproducing apparatus a light emitting device emitting a laser beam radiated on the surface of an optical disk is used for both recording and reproduction during recording and reproduction, respectively. For that reason, it is impossible to record pictures or the like and reproduce the pictures which have been just recorded, during recording, to monitor the recording device.
As stated above, since there is no conventional optical disk reproducing apparatus of such a type as simultaneously emitting two or more recording laser beams, it is impossible to record image information or the like, and reproduce and monitor the image information which has been recorded during recording. Owing to this, if the recorded information is reproduced after all recording processings have been completed, it includes noise and recording processings need to be started over again, which is quite inconvenient.
Furthermore, in a master disk recorder in which two laser beams of different wavelengths are simultaneously radiated, two laser spots are manually adjusted by observing the spot positions. The master disk recorder, however, has disadvantages in that it requires labor since a guide beam is arranged in front of a recording beam to monitor a state just before recording, a guide beam is arranged in back of a recording beam to check a recording state right after recording or the like.
Additionally, there is no optical disk recording/reproducing apparatus in which a recording beam and a reproduction beam are individually provided. For that reason, to check a recording-state, reflection light during recording has been conventionally checked, for example. In recording operation, however, the quantity of reflection light tends to be greatly irregular, with the result that accuracy for calibrating recording power cannot be disadvantageously increased.
Meanwhile, a master disk recorder is capable of monitoring a state in which data is recorded with a recording beam, by means of a guide beam; however, after monitoring a recorded state, the quantity of recording light beam is not subjected to real-time feedback. The positions of two laser spots slightly vary with environment such as temperature. In the master disk recorder, these variations are adjusted every time they are found. The problem with an optical disk apparatus used by an ordinary user, on the other hand, is that the user is incapable of adjusting the optical axis of the apparatus.
It is, therefore, an object of the present invention to provide an optical apparatus used for an optical disk recording/reproducing apparatus capable of realizing high reliability in recording operation by independently providing a recording beam and a reproducing beam.
The present invention is an optical apparatus for an optical disk recording/reproducing apparatus, comprising first emitting means for emitting a recording beam for recording data on an optical disk; second emitting means, provided near the first emitting means, for emitting a reproducing beam for reproducing the data recorded on the optical disk; and detecting means for receiving and detecting light of the reproducing beam emitted from the second emitting means.
According to the present invention, as described above, a recording beam and a reproducing beam dedicated to recording and reproduction, respectively, are provided. This makes it possible to record data on a disk and reproduce the data while data is still recorded. Due to this, it is possible to monitor a recording state while data is recorded. Thus, compared with a conventional apparatus in which a bad recording state is discovered only after data recording is completed, it is possible to ensure recording data according to the present invention. It is also possible to adjust, for example, a focus or track direction or to adjust the light power of a recording beam and a reproducing beam or the like simultaneously with data recording according to the present invention.
Moreover, the present invention is an optical apparatus for an optical disk recording/reproducing apparatus, comprising first emitting means for emitting a first beam onto an optical disk; second emitting means, provided near the first emitting means, for emitting a reproducing beam for reproducing data recorded on the optical disk so that a wave front aberration is 0.07xcex or less, the wave front aberration being generated when a second beam is, arranged near the first beam emitted from the first emitting means; and detecting means for receiving and detecting at least one of reflection light of the first beam emitted from the first emitting means and reflection light of the second emitting beam emitted from the second emitting means.
With the above-stated structure, the present invention clearly specifies a limit in a case where the first beam and the second beam are emitted on the disk while being separated from each other to a maximum without overlapping each other. In other words, the arrangement of the two beams indicated by the Marechal""s limit requires that the wave front aberration caused by separate emission be 0.07xcex or less. The present invention provides an optical apparatus capable of ensuring correct data recording and reproduction as long as the beams are emitted within that range.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.